Hey man i forgot to say, for DA when it comes to things like this i would set the Res at 1280 x 720 so it's not laggy for people with laptops that only go to 1300 to 1600 res or whatever then full 1080 for youtube and other things ( guessing that you use image render then import to Flash where settings like this can be change easy. )

oh ok , then yes your first idea is correct then just render in 720p , the reason to do all that extra 1080p stuff was because i thought you want full HD etc but here on DA that does not work (To my knowledge) it needs to be medium size or it will Overshoot people screens / choppy